Paint-spraying machine



April 15 1924. 1,490,337

J.D.MURRAY PAINT SPRAYING MACHINE Filed Nov`.,10; 1922 Fjgj.

operated by the application of a fluid acting Patented pr. l5, E924,

TOEN D. MURRAY, 0F SAN FRANCISCO, CALIFORNIA.

rerNr-srnarrne MACHINE.

Application led November 10, 1922. Serial No. 599,993.

To all whom it may concern.'

Be it known that I, JOHN D. MURRAY, a citizen of the United States, residing at city and county of San Francisco and State of California, have invented certain new and useful Improvements in Paint-Spraying Machines, of which the following is a speci'- lication.

The present invention relates particularly to an apparatus for containing and discharging liquids such as paint and the like, and is on a movable element or piston whereby the liquid body is raised within the apparatus and is ejected or forced therefrom.

The invention is particularly designed for the application of paint Iby an air brush method although it is capable of being used ordcoating any surface with any suitable The principal objects of this invention are to provide an improved form of piston acted on by fluid pressure and against which the fluid pressure exerts an uniform pressure in all directions, preventing the jamming of the piston within the apparatus. Another object is to provide a construction wherein the valve controlled outlet is carried by the apparatusI cover and which is readily removable permitting access to the entire interior of the apparatus. A. further object is to provide a novel form of cover clamp and also to provide a fluid supply system entering` the base of the apparatus for elevating the piston therein.

With the above mentioned and other objects in view the invention consists in the novel construction and combination of parts, hereinafter described, 'illustrated in the accompanying drawings, and pointed out in the claims hereto appended; being understood that various changes in the form, proportion, size and minor details of construe# tion within the scope of the claims may be made without departingfroin the spirit or sacrificing any of the advantages of the im vention.

Figure 3 is a transverse sectional view Ataken on line 3-3 of Fig. 1 and casting and provided at opposite sides with respective channels 2 and 3, and provided withl an upstandiiig annular flange 4 to which is secured the lower edge or end ot' a cylinder 5 which forms a container. The

. channel 2 opens at one end as'at 6 into the base or bottom of the container and at its opposite end which is exterior of the fiange Il carries a relief valve 7,; The channel 3 also opens as at 8 into the bottom of the container and with its outer end connects a pipe 9 within which is positioned a valve 10 and above said'valve is a T coupling 11 mounting a three way valve 12 controlled by a stem 13. Fluid, preferably air, is admitted into the T' coupling through a pipe 14 and depending on the position of the three way valve 12 may be conducted downwardly in pipe 9 and also into pipe 15 connected with said T coupling or the valve12 may be rotated to conduct all of the fluid pressure into pipe 9 or may be moved to conduct the Huid pressure ina straight path from the pipes 14: to 15.

The upper opened end of the container is adapted to be closed by a cover 16 preferably in the form of a fiat plate or disk, and said cover' is provided with an annular groove 17 within whicliis received the upper edge of the member 5. The'cover is .formed with a duct 18 extending therethrough from edge to ed e and the same` connects through a latera 19 with the interior of the container. A valve 20 mounted in one end of the duct 18 and operated by the stein'21 which extends through a gland 22 is adapted to control the passage of material from the `container through the port 19 into the duct l18.

-With the opposite end of the duct 18 is connected tlirou h a coupling 23 a hose or other tubular condiiricting element 24.

To maintain the' cover tightly positioned on the upper edge of the member 5 to close the container l provide parallel rods 25 fulcrumed at their lower ends as at 25 to the members 26 at opposite sides of the base 1.

The rods are connected at their upper ends by a bridle 27 adapted to extend transversely over the cover disk and said bridle mounts a clamping screw 28 which in turn carries an adjusting wheel 29 for imparting movement thereto to force the-samefin tight Contact with the center of the disk and to maintain the same in position on the container.

Dividing the interior of the container into upper and lower chambers the upper adapted for containing the liquid such aspaint, and free to reciprocate therein, is a piston consisting 'of a body 30 annularly recessed about its periphery as at 3 1 and within which recess is positioned a packing 32 supported b The upper surface of the piston carries a face plate 34 forming a floor or support on which the paint or liquid in the upper portion of the chamber rests, the plate being solely supported by its peripheral edge resting on the packing 32. To equalize the strain and pressure on the under side of the piston the under surface of the body is provided with a concave recess o5 the periphery of which terminates short of the periphery of' the body. The Huid, preferably air, admitted through the channel 3 acts on the under surface of the piston and elevates the same within the container at the same time maintaining the side Walls of the packing parallel with the side walls of the container preventing the jamming of the piston Within the container and overcoming the necessity of guides which have been heretofore required. l

In the operation of the device the cover 16 is removed and the paint or material to be discharged from the container is deposited therein on the face 34 of the piston. The cover is then placed in position and the open top of the container is sealed by the adjustment of the screw 28. The valve 20 is then opened as is valve 10 and the three way valve 12 is adjusted to admit fluid pressure, preferably air, into the base of the container through the channel 3. The air pressure accumulating in the base of the container acts on the concave under surface of the piston to gradually force the material through the duct 18. This is accomplished yployed.

a flange 33 projecting below the recess `said piston being concave, an

without the air mixing with the iiuid 0r material contained within the upper portion of the container and thus overcoming the liability of oxidization when paint is em- After the material has been discharged from the container the valve 7 may be opened which will release the pressure in the base of the container and permit the piston to drop by gravity.

It will be apparent that the paint may be forced downwardly in said pipe 24 and duct 18 and returned to the interior of the container by air 4pressure forced downwardly in pipe 24, This action will clear the pipe 24 and channel 18 and will also force the piston downwardly `in the container.

Having thus described my invention, what I claim as new and desire to protect by Letters Patent of ,the United States is 1. A liquid discharging apparatus including a container for the liquid, said container provided with a valve controlled liquid discharge at its upper end, and provided with a valve controlled `fluid inlet communicating with its interior at its bottom, a fluid operated liquid elevating piston forming a bottom wall for the liquid, the under side of annular packing carried by the piston for engaging the container wall, and a piston face plate resting on one edge of said packing.

2. A liquid dis xharging apparatus including a container for the liquid and provided with a valve controlled liquid discharge at its upper end, a valve controlled 4fluid inlet communicating with the `interior of the container at its bottom, a fluid operated liquid elevating piston mounted to reciprocate within said container, said piston having a relatively Wide periphery and formed on its under side with a concave recess, a packing disposed peripherally of the piston for engaging the side walls of the container, and a Yface plate covering the upper surface of the piston and solely supported by said packing whereby on the application of pressure to the under side of said piston,-the load resistance disposed by `said face plate will compress said packing.

ln testimony whereof l have signed my name to this specification.

JGHN D. MURRAY. 

